Keisuke Yoshida, Masaoki Uno, Dan Bassett
Abstract The 2025 Mw 7.6 Aomori‐Oki earthquake nucleated near the 1968 Mw 8.3 Tokachi‐Oki rupture area. Our waveform inversion reveals large slip (>1 m) extending ∼40 km northward from the hypocenter, overlapping the inferred 1968 northern asperity. Minor secondary slip (0.2–0.6 m) was resolved ∼60 km updip, and high‐precision relocations show that major aftershocks, including the Mw 6.7 and 6.6 events, clustered nearby. The relocated aftershocks form multiple streaks aligned with plate convergence. Terminating one such streak, the Mw 6.7 sequence formed a dense circular cluster correlating with a local bathymetric high. At a broader scale, the 2025 Aomori‐Oki sequence and historical M ≥ 5 events delineate a slip‐parallel belt that extends trenchward across a prominent tremor gap and broadly coincides with gravity‐anomaly lineations. Together, these observations suggest that structural heterogeneity imposed by subducting plate roughness and inherited upper‐plate structures modulates rupture initiation, rupture growth, and rupture arrest.